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Publication numberUS5043075 A
Publication typeGrant
Application numberUS 07/528,578
Publication dateAug 27, 1991
Filing dateMay 24, 1990
Priority dateJun 8, 1989
Fee statusLapsed
Also published asCA2017689A1, DE59002166D1, EP0402347A1, EP0402347B1
Publication number07528578, 528578, US 5043075 A, US 5043075A, US-A-5043075, US5043075 A, US5043075A
InventorsKorger Dietmar, Stephan Astegger, Dieter Eichinger, Heinrich Firgo
Original AssigneeLenzing Aktiengesellschaft
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Method of removing amines
US 5043075 A
There is disclosed a method of removing amines from aqueous solutions thereof, in particular from waste waters obtained in cellulose processing. The aqueous amine solutions are contacted with a cation exchanger whose anchor groups consist of carboxyl groups, in order to charge the cation exchanger with the amines. The charged cation exchanger is treated with an aqueous solution of a weak acid having a pKa larger than 3.0 in order to elute the amines. The eluate is processed by way of distillation, wherein a portion of the weak acid is separated from the amines and reclaimed, if desired.
The method according to the invention offers a simple and cheap way of disposing amine-containing waste waters.
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What we claim is:
1. A method of removing amines form an aqueous solution containing amines, which method comprises the steps of
providing a cation exchanger having anchor groups essentially consisting of carboxyl groups,
contacting said aqueous amine solution with said cation exchanger so as to obtain said cation exchanger charged with said amines,
preparing an aqueous acid solution of a weak acid having a pKa larger than 3.0,
treating said cation exchanger charged with said amines with said aqueous acid solution so as to elute said amines, thus obtaining an eluate, and
processing said eluate by way of distillation so as to cause a portion of said weak acid to be separated from said amines.
2. A method as set forth in claim 1, further comprising the step of reclaiming said portion of said weak acid separated from said amines.
3. A method as set forth in claim 1, wherein said weak acid has a boiling point of below 120 C.
4. A method as set forth in claim 1, wherein said weak acid is selected from the group consisting of formic acid, acetic acid and carbonic acid.
5. A method as set forth in claim 1, wherein said aqueous acid solution of said weak acid has a pH ranging between 1.7 and 2.8.

The invention relates to a method of removing amines from aqueous solutions thereof, in particular from waste waters obtained in certain cellulose processing methods.

Such amine solutions constitute a problem of waste disposal, because hitherto no method has been known, by which amines can be removed from such waste waters in high yields and in a simple manner. Many amines are known to be toxic and difficult to degrade.

Distillative separation methods are described in the literature. Yet, at amine concentrations of 0.01 to 5% by weight, these methods involve several steps, thus being rather complex and uneconomic.

Even various extraction methods have been tested for removal, having been combined with subsequent distillation. Such a method is known, for instance, from GB-B-1 073 582. However, the amines cannot be removed completely according to this method.

In the journal Khim.Prom-st. (Moscow) 1983 (2), pp. 83 to 85, a method of completely removing morpholine from waste waters is described. According to this method, removal is effected by means of ion exchange. The disadvantage of this method consists in that a plurality of ion exchangers, i.e., two strongly acidic cation exchangers combined with an anion exchanger, must be used and that the morpholine-containing eluates resulting from regeneration are strongly acidic and must be neutralized with adequately large amounts of caustic solution prior to further processing. However, the salts incurred entrain morpholine during crystallization, which, in turn, is disadvantageous in that the salt cannot be waste-disposed directly, but only after further regeneration.

The invention has as its object to eliminate these disadvantages and to provide a simple method of removing amines from aqueous solutions thereof, which is feasible in a cost-saving manner requiring no neutralization step and no energy-consuming separation and regeneration steps.

The method according to the invention is characterized by the combination of the following measures:

contacting the aqueous amine solutions with a cation exchanger whose anchor groups consist of carboxyl groups, in order to charge the cation exchanger with the amines,

treating the charged cation exchanger with an aqueous solution of a weak acid having a pKa larger than 3.0 in order to elute the amines, and

processing the eluate by way of distillation, with a portion of the weak acid being separated from the amines and reclaimed, if desired.

By the ion exchanger used according to the invention, the amines both can be removed practically quantitatively in a single pass and can be re-eluted with weak acids. Among these, volatile acids having boiling points of below 120 C., such as formic acid, acetic acid or carbonic acid, have proved particularly suitable.

An advantageous embodiment of the method according to the invention consists in that the pH of the aqueous solution of the acid ranges between 1.7 and 2.8.

The eluate, which contains the amines, acid and water, is further processed by distillation, the distillate containing the acid, water and merely traces of amines and, thus, being apt for recycling into the process. It may, for instance, be used for rinsing the ion exchanger after regeneration. Moreover, it is possible to prepare a fresh regenerant solution by adding concentrated acid. The amines remain in the distillation residue in the form of ammonium salts, e.g., as formates and acetates, together with acid residues. The amines present in a concentrated form can be further processed according to various methods described in the literature or, preferably, can be disposed by being burnt completely.

The invention will be explained in more detail by way of the following examples.


50 ml LEWATIT CNP 80 (a cation exchanger whose anchor groups consist of carboxyl groups) (manufacturer: Bayer AG) were charged with 100 ml of an aqueous solution containing 4.9 g N-methyl morpholine (pH=10.03). Subsequent elution was effected with 200 ml 10% acetic acid. The eluate contained 4.6 g N-methyl morpholine. After this, the ion exchanger was washed with 400 ml distilled water. An additional 0.2 g N-methyl morpholine was found in the washings.

Thus, the amine was removed from the aqueous solution by 98% and readily disposed by burning. The distillate was used to prepare new elution solutions.


50 ml LEWATIT CNP 80 were charged with 500 ml waste water from cellulose processing (pH=10.31) containing 0.15% by weight N-methyl morpholine and morpholine. Elution was effected with 150 ml 10% acetic acid, whereupon washing was performed with 300 ml distilled water. Subsequently, distillation was carried out, 42.6 g condensate with an acetic acid concentration of 3.3 % being obtained from 123 g eluate (acetic acid concentration: 4.7%). The distillation residue was comprised of 5.5% acetic acid, 0.36% amine and water. By adding acetic acid to this, the elution solution for the following Example 3 was prepared, the amine having no adverse effect.

The amine was removed from the waste water by 94%.


50 ml LEWATIT CNP 80 were charged with 1000 ml waste water (pH=9.88) containing 2.86 g N-methyl morpholine. Subsequently, elution was effected with the distillation residue incurred in Example 2 and enriched with acetic acid to 10.4%. Thereby, the amine concentration fell to 1.54%. 148.2 g of this solution were required for elution. 198.2 g eluate incurred, containing 6.09% acetic acid and 2.18% amine. Thus, 72% of the amine could be eluted even without washing,.

Processing and disposal were effected as in Example 1.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2585490 *Mar 31, 1949Feb 12, 1952Sun Oil CoContinuous adsorption process
US3475330 *Dec 5, 1967Oct 28, 1969Continental Products Of TexasMethods of removing and reclaiming ammonia ions from water
US3939071 *Aug 12, 1974Feb 17, 1976Aerojet-General CorporationRecoverable regenerants for cationic exchange resins
US4197195 *Nov 8, 1977Apr 8, 1980Gesellschaft Fur Kernforschung M.B.H.Method for minimizing the organic waste in aqueous product streams produced in liquid-liquid extraction processes
US4518503 *Mar 29, 1984May 21, 1985Intercontinental Water Corp.Water purification method and device
US4655929 *Apr 1, 1985Apr 7, 1987Mitsubishi Kinzoku Kabushiki KaishaProcess for processing waste solution containing ammonium ions and fluoride ions
US4904383 *Mar 7, 1989Feb 27, 1990Auerswald David CSystem for demineralizing water
AT336510B * Title not available
GB1073582A * Title not available
Non-Patent Citations
1 *Isaeva et al., Khim. Prom st. (Moscow) 1983 (2); pp. 83 85 (English abstract).
2Isaeva et al., Khim. Prom-st. (Moscow) 1983 (2); pp. 83-85 (English abstract).
Referenced by
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US5409532 *Jan 21, 1993Apr 25, 1995Lenzing AktiengesellschaftAmine-oxides
US5503749 *Aug 2, 1994Apr 2, 1996Lenzinc AktiengesellschaftProcess for the purification of aqueous solutions of amine-oxides
US5942122 *Apr 1, 1996Aug 24, 1999Ngk Insulators, Ltd.Method of deodorizing ion-exchanged purified water
US6113799 *Apr 17, 1997Sep 5, 2000Lenzing AktiengesellschaftProcess for selective separation of morpholine
US7300468May 23, 2005Nov 27, 2007Whirlpool Patents CompanyMultifunctioning method utilizing a two phase non-aqueous extraction process
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US7758757Jul 20, 2010E. I. Du Pont De Nemours And CompanyMethod for removing hydrazine compounds
US7837741Apr 12, 2005Nov 23, 2010Whirlpool CorporationDry cleaning method
US7966684Jun 28, 2011Whirlpool CorporationMethods and apparatus to accelerate the drying of aqueous working fluids
US8262741Sep 11, 2012Whirlpool CorporationNon-aqueous washing apparatus and method
US8545704 *May 30, 2008Oct 1, 2013Soonchunhyang University Industry Academy Cooperation FoundationMethod for recovering amine from amine-containing waste water
US8911538Dec 22, 2011Dec 16, 2014Alstom Technology LtdMethod and system for treating an effluent stream generated by a carbon capture system
US20090101589 *Oct 19, 2007Apr 23, 2009Kiu-Seung LeeMethod for removing hydrazine compounds
US20090172891 *Mar 12, 2009Jul 9, 2009Whirlpool CorporationMethod and apparatus for cleaning objects in an automatic cleaning appliance using an oxidizing agent
US20110100917 *May 30, 2008May 5, 2011Soonchunhyang University Industry Academy Cooperation FoundationMethod for Recovering Amine From Amine-Containing Waste Water
U.S. Classification210/664, 203/41, 210/673, 210/677, 210/670
International ClassificationC07C209/86, C02F1/42, C07D295/02, B01J39/04
Cooperative ClassificationB01J39/046, C02F1/42
European ClassificationB01J39/04D, C02F1/42
Legal Events
May 24, 1990ASAssignment
Effective date: 19900510
Mar 2, 1993CCCertificate of correction
Jan 23, 1995FPAYFee payment
Year of fee payment: 4
Feb 16, 1999FPAYFee payment
Year of fee payment: 8
Mar 12, 2003REMIMaintenance fee reminder mailed
Aug 27, 2003LAPSLapse for failure to pay maintenance fees
Oct 21, 2003FPExpired due to failure to pay maintenance fee
Effective date: 20030827